Wladimir will always be seen as the more vurnerable as the two; Vitali as the stronger one.

Wladimir has much better wins than Vitali, but also much worse losses.

To me, Wladimir is much better. Better handspeed, coordination and technique. I think it more than compensates for what he lacks in chin compared to Vitali. That said, Vitali does get the job done often with his weird style.

Personally, I rate Wlad as the better of the two in terms of accomplishments. That said, Vitali was the more dangerous of the two, although I'd give an edge to the more technically sound Wlad to upset Vitali.